|
Complex biological macromolecules such as proteins can experience prominent structural transitions under variation of the thermodynamical parameters of surrounding water environment. Among these parameters are temperature, pressure, ion concentration, pH value, etc. [1]. One of the most discussable class of structural transitions in proteins is the folding - unfolding transition. Folding process of protein can be understood as prominent change of the 3D structure of the molecule which is accompanied by a peculiarity in the thermodynamical functions of the system such as the internal energy, heat capacity, etc. We present a statistical mechanics formalism for the description of the folding - unfolding transition of proteins in water environment [2-4]. Our formalism is based on the construction of the partition function of the infinitely diluted water solution of proteins. With our statistical mechanics model we are able to describe the most of the peculiarities of protein's heat capacity on temperature dependence in a wide range of temperatures. Among these peculiarities are the residual increase of the heat capacity of the protein in the unfolded state, the existence of the cold denaturation transition for certain proteins, height and broad-width of the heat-capacity curve under different environmental conditions. We present the comparison of the results of our theoretical model with the experimental measurements of the denaturation curves of two globular proteins, namely metmyoglobin and staphylococcal nuclease.
Another very important issue concerns to the dynamics of protein's denatration under ultrafast heating events such as propagation of the charged particle in the water medium. The study of these processes is of primary importance for understanding of the biological effects of the ion-beam tumor therapies [5,6]. We present the results of molecular dynamics simulations of the proteins experiencing a carbon ion propagation at various distances from the track. The effects of ion propagation on protein's structure are thoroughly analyzed.
References [1]A.V. Yakubovich, I.A. Solov˘yov, A.V. Solov˘yov, Europhysics News, 38, 10 (2007) [2]A.V. Yakubovich, Solov˘yov, W. Greiner, accepted to Int. J. Quant. Chem. http://www3.interscience.wiley.com/journal/122428327/abstract [3]A.V. Yakubovich, I.A. Solov˘yov, A.V. Solov˘yov, W. Greiner, European Physical Journal D 46, 215, (2008) [4]I.A. Solov˘yov, A.V. Yakubovich, A.V. Solov˘yov, W. Greiner, European Physical Journal D 46, 227, (2008) [5]E. Surdutovich, A.V. Solov'yov, Europhysics News 40, p.21-24, (2009) [6]A.V. Solov'yov, I. Mishustin, E. Surdutovich, E. Scifoni, W. Greiner, Phys. Rev. E 79, p.011909-(1-7) (2009) |
|